Actuator for controlling devices



April 5, 1932. PHELAN 1,852,333

' ACTUATORFOR CONTROLLING DEVICES 1 Filed April 28, 1928 vPatentedApr.1932 I UNITED STATES PATENT OFFICE LOUIS A. Mi PHELAN, OF EIIKHABT,INDIANA, ASSIGNOB, BY MESNE ASSIGNMENTS, 'I'O MINNEAQOLIS-HONEYWELLREGULATOR COMPANY OF MINNEAPOLIS, MINNESOTA,

A CORPORATION OF DELAWARE ACTUATOR FOR CONTROLLING DEVICES Applicationfled April 28,

means, the latter controlling electrically operated devices or systems.

More particularly, this invention has reference to an electricallyheated actuator comprising opposed bimetallic members that areinterconnected whereby when the bimetallic .members are heated or cooledthe bimetallic members warp or buckle away from each other or towardeach other to actuate an electric switching mechanism.

The device of this invention is shown and will hereinafter be describedin connection with an elecg'ical switch employing a t1ltable liquidcont-actor tube, the latter being arranged to m'ake and break anelectrical circuit therethroiigh. It will be particularly noted that amaximum leverage is obtained by the actuator and that a minimum amountof space is required to house the same. A comparison may be had byreferring to an ordinary electrically heated actuator comprising anelongated strip of bimetallic material which is fixed at one end, thewarping of z the actuator causing the free end thereof to move thelinkage mechanism of an electrical switch.

The device of the present invention obviously may be considerablyshorter than the aforementioned type of actuator and further a greateramount of power may be developed in the resent device from the sameamount of available thermal energy because of the greatly increasedleverage. Also because of the arrangement of the elements of theactuator the degree of movement thereof may be multiplied a reat numberof times for a given degree of heat as it may be desirable to obtain anactuation of the-switching mechanism of the device when a change of buta sin ledegree of temperature is recorded.

urther obj cts and advantages will hereinafter be pointed out and for abetter understanding of the characteristic features of this inventlon,reference may now be had to the following description and theaccompanying drawings, in which:

1928. Serial No. 278,505.

Figure 1 is a front elevational view of a switching mechanism embodyingtiltable fluid contact making-and-breaking members actuated by thedevice of the present invention;

Fig. 2 is a perspective view of the thermally operated actuator;

Fig. 3 is a perspective view-of the various elements of the device ofFig. 2 in a spaced relation with each other;

Fig. 4 is a side elevational view of a modi- 'fied form of a thermallyoperated actuator embodying my invention and emplo ing a plurality ofunits such as is shown in ig. 2;

Fig. 5 1s a slde elevational view of a further modification of mythermally operated actuator showing the elements thereof connectedtogether at a central point; and

Fig. 6 is a side elevational view of a still further modification of mythermally operated actuator showing the elements thereof connected atone end.

Referring now to the drawings and more particularly to Figs. 1 to' 3,inclusive, a thermally operated actuator 10 is shown comprismg a pair ofbimetallic elements 11 and 12 having a resistor 13 disposedtherebetween, the resistor being insulated from the bimetallic elementsby means of the strips of mica 14 and 15 or by means of any suitableinsulating material.

Each of the bimetallic elements 11 and 12 comprises preferably a stripof invar metal 16 which has been suitably united with a strip of brass17 in a manner well known in the art to constitute the so-calledbimetallic thermostat. The materials just recited are preferably usedalthough it is to be understood that any two metals, intimately unitedover their adjacent and abutting surfaces for obtaining a movement. ofone part thereof relatively to the other part under temperature changes,may be employed. It is only necessary that the two metals have differentcoefficients of expansion. Hereinafter one of the metals will bereferred to as bein of the higher order and the other metal Wlll. berewire 18 wound therearound in a spaced relation to form an electricalheating coil. In winding the resistance wire 18 about the core or stripof mica the wire may imbed itself in the corners of the mica and in thatmanner each convolution will be held in a spaced relation.

The strips of mica 14 and 15 are provided with projecting portions 19having holes 20 formed therein for receiving binding posts 21, the endsof the resistance wire 18 being connected thereon.

The invar metal 16 is provided with ears 22 which extend beyond theconfines of the brass strips 17, the corresponding ears of one of theinvar metal strips being connected to corresponding ears of the other ofthe invar metal strips as by means of rivets. It will be notedparticularly that the invar metal strips are spaced adjacent each otherand that the brass strips therefor are disposed on the outer sidesthereof whereby the bimetallic members 11 and 12 are opposed to eachother during the actuation thereof.

In the arrangement of the bimetallic elements, in each of the followingillustrations, the material of the same order of each element, isdisposed adjacent each other.

In the operation of the heat responsive device 10, when an electricalcurrent is passed through the resistance wire 18, the bimetallicelements 11 and 12 are heated and thereafter warp in a manner in whichtheir coefficients of expansion direct. By referring to '1, it will benoted that the bimetallic members of the heat responsive device 10 arebellied or warped away from each other, those elements beiang connectedat both their lower and upper en s.

In order that a specific illustration of an actual use be had, one ofthe bimetallic elements 12 has a screw 23 fixedly mounted thereon whichis secured in any ordinary manner to an insulating post 24. The otherbimetallic element 11 has a post 25 secured thereto and a pin 26 mountedin the post 25 to engage an aperture in a pivotally mounted arm 27. Thefree end of the arm 27 is connected by a suitable link member to asecond arm 28 for actuatinga tiltably mounted mercury contactor tube 29which latter is of the usual type and comprises a sealed containerhaving a pair of spaced cooperating electrodes disposed in one endthereof to be bridged by a body of current conducting fluid. such asmercury, when tilted in one direction. It will be readily apparent thatthe heating of the bimetallic elements 11 and 12 will actuate the arm 27to tilt the contactor tube 29. Likewise, the cooling of the bimetallicelements 11 and 12 will actuate the arm 27 to tilt the contactor 29 in adirection to change the circuit connections therethrough.

In order that the degree of movement maybe multiplied a great number oftimes for a given degree of temperature, a plurality of i heatresponsive devices 10 are joined together as in Fig. 4, each ofthebimetallic elements being opposed, that is, the members of similarorders of expansion being disposed adjacent each other. It will be notedthat the outside metal of the element which, in the present instance,may be brass, is disposed adjacent the brass strip of the adjoiningelement. It has already been pointed out that the inner strips of metal,in this particular instance, the invar metal, are connected together. Itis quite apparent that should the movement of one of the members be aquarter of'aninch, the movement of four such members when connectedtogether wouldbe a full inch. It is also to be understood that theresistor 13 may be omitted from this construction when it is desirablethat the operation of the actuator be controlled by the temperature of aroom as is the ordinary thermometer.

In order to show the operation of the plurality of bimetallic elements,each unit 10 is connected at a central point to each other, one of theunits being fastened to the insulating post 24 and the other end elementbeing connected by means of a link 30 to an arm 31 of a pivotallymounted mercury contactor 32 whereby the expansion or contraction of theunits will tilt the contactor to obtain a change of circuit connectionstherethrough.

By referring now to Fig; 5, the bimetallic elements 11 and 12 arecentrally connected as by means of a rivet 33, one end of the element 12being pivotally connected to a bracket 34 and the other end thereofbeing slidably connected to a bracket 35. The element 11 is pivotallyconnected to one end of the link 36, the other end of the element beingslidably connected to the other end of the link 36. The warping of thebimetallic elements 11 and 12 move the link 36 away from the insulatingpost 24 to which the brackets 34 and 35 are secured to actuate acontactor tube 37.

By referring now to Fig. 6, a still further modification is shown inwhich the bimetallic elements 11 and 12 are connected together at oneend, that end being secured to an insulating post 24. The free end ofthe bimetallic element 12 is slidably connected to a bracket 38 which isfixedly mounted on the mounting plate on which the insulating post 24 isfixedly mounted and the free end of the bimetallic element 11 isconnected as by means of the link 39 to an arm 40 of a tiltably mountedmercury contactor tube 41. y

In each of the modifications just described, the actuation of thebimetallic elements is multiplied in order to obtain a maximum leveragein a. minimum amount of space. As a result of this invention, a maximumamount of power may be developed in a device which will occupy but aminimum amount of space. due to the arrangementsof the elements enteringinto the construction obtaining a maxiroom tem erature ma be the enerfor controlling the actuation oi the device where it is not desirable tocontrol the same by means of electrical energy in the electrical circuitin which the device may be operated.

While but a single embodiment of this invention is herein shown anddescribed, it is apparent that various modifications "iElIGTGO'i may beapparent to those skilled in the art without departing from the spiritand scope of this invention, and therefore, the same is to be limitedonly by the scope of the prior art and the appended claims.

. I claim: I

1. A heat responsive device comprising a plurality of side-by-sidebimetallic members, the materials of each member having differentcoefiicients of expansion and the material of the several memberspossessing simi-' lar coefiicients of expansion, being disposed adjacenteach other, said members being mechanically attached to one another inorder that their several distortions will be additive, and an electricheater independent of said members but interposed therebetween fordistorting said elements.

2. In combination with a mercury con-- tactor adapted to control anelectric circuit, of a heat responsive actuator therefor com prising apair of opposed bimetallic elements that are attachedto each other tosupplement the degree of distortion of one of said elements with thedegree of distortion of the other of said elements, an electricheatingelement interposed between said elements, and means for impartingto said contactor the resultant distortion of both elementsofsaidactuator.

3. In combination with a tiltably mount ed mercury contactor, of a heatresponsive" actuator therefor comprising a plurality of opposedbimetallic elements that are attached to each other to supplement thedegreeof distortion of one of said elements with the degree ofdistortion of the other, of said elements, an electric heater for in.fluencing said bimetallic elements, and means interposed between saidcontactor and said actuator for imparting to the former the resultantmovement arising from the to tilt said contactor. i

4. In combination with a mercury rpntactor adapted to control anelectric circuit, of a heat responsive actuator therefor comprising aplurality of opposed flexible bimetallie elements that are attached toeach'other to supplement the degree of distortion of one of saidelements withthe degree of distortion of the othei'lqf said elements,an'eleotric heater interposed between at least two of said elements andindependent-thereof latter" cent to each other, ears projecting fromeach whereby said elements may become distorted loy the heat generatedin saidelectric heater, means responsive to the distortion of saidelements for imparting to said contactor the resultant distortion oi allof said elements.

5'. In comhination with a mercury contactor adapted tocontrol anelectric circuit, of a heat responsive actuator therefor co1nprisingaplurality of side-by-side and op posed bimetallic elements that areattached to eachother to so pl-ement the degree of distortion of one orsaid elements with the degree of distortion oi the other of saidelements, an electric heater interposed between at least two oi saidelements and independent thereof whereby said elements may flex withoutbeing mechanically restrictedby said electric heater, and meansinterposed between said contactor and said actuator for imparting tosaid contactor the resultant distortion of all of said elements.

6. In combination with a tiltably mounted mercury contactor adapted tocontrol an electric circuit, of a heat responsive actuator thereforcomprising a plurality of opposed bimetallic elements that are attachedto each other to supplement the degree of distortion of one of saidelements with the degree of distortion of the other of said elements, an

the 'materials of each element having different coefficients ofexpansion and the material of the elements possessing similarcoefficients of expansion being disposed adjacent to each other, earsprojecting from each of said elements, said ears being integral withonly one of the materials comprising said elements, means for attachingsaid elements to each other through the medium of-said ears, and anelectric heater independent of said elements for distorting them.

8. A heat responsive device comprising a plurality of side-by-sidebimetallic elements, the materials of each element having dif ferentcoeificients of expansion and the ma terial of the elements possessingsimilar coeflicients of expansion being disposed adjaof said elements,said ears being integral with only one, of the materials comprising saidelements, and means for attaching said elements to each other throughthe medium of said ears.

In Witness whereof l have hereunto subscribed my name.

LUUIS A. M. PHELAN.

